Matthias F. Oertel

Energy dysfunction as a predictor of outcome after moderate or severe head injury: indices of oxygen, glucose, and lactate metabolism.

The purpose of this study was to determine if the relationship between abnormalities in glucose, lactate, and oxygen metabolism were predictive of neurologic outcome after moderate or severe head injury, relative to other known prognostic factors. Serial assessments of the cerebral metabolic rates for glucose, lactate, and oxygen were performed using a modified Kety-Schmidt method. In total, 31 normal control subjects were studied once, and 49 TBI patients (mean age 36±16 years, median GCS 7) were studied five times median per patient from postinjury days 0 to 9. Univariate and multivariate analyses were performed. Univariate analysis showed that the 6-month postinjury Glasgow Outcome Scale (GOS) was most strongly associated with the mean cerebral metabolic rate of oxygen (CMRO2) (P = 0.0001), mean arterial lactate level (P = 0.0001), mean arterial glucose (P = 0.0008), mean cerebral blood flow (CBF), (P = 0.002), postresuscitation GCS (P = 0.003), and pupillary status (P = 0.004). Brain lactate uptake was observed in 44% of all metabolic studies, and 76% of patients had at least one episode of brain lactate uptake. By dichotomized GOS, patients achieving a favorable outcome (GOS 4-5) were distinguished from those with an unfavorable outcome (GOS1-3) by having a higher CMRO2 (P = 0.003), a higher rate of abnormal brain lactate uptake relative to arterial lactate levels (P = 0.04), and lesser degrees of blood-brain barrier damage based on CT findings (P = 0.03). Conclusions: During the first 6 days after moderate or severe TBI, CMRO2 and arterial lactate levels are the strongest predictors of neurologic outcome. However, the frequent occurrence of abnormal brain lactate uptake despite only moderate elevations in arterial lactate levels in the favorable outcome patients suggests the brains ability to use lactate as a fuel may be another key outcome predictor. Future studies are needed to determine to what degree nonglycolytic energy production from alternative fuels such as lactate occurs after TBI and whether alternative fuel administration is a viable therapy for TBI patients.

Clinical and methodological precision of spinal navigation assisted by 3D intraoperative O-arm radiographic imaging

OBJECT In recent years, the importance of intraoperative navigation in neurosurgery has been increasing. Multiple studies have proven the advantages and safety of computer-assisted spinal neurosurgery. The use of intraoperative 3D radiographic imaging to acquire image information for navigational purposes has several advantages and should increase the accuracy and safety of screw guidance with navigation. The aim of this study was to evaluate the clinical and methodological precision of navigated spine surgery in combination with the O-arm multidimensional imaging system. METHODS Thoracic, lumbar, and sacral pedicle screws that were placed with the help of the combination of the O-arm and StealthStation TREON plus navigation systems were analyzed. To evaluate clinical precision, 278 polyaxial pedicle screws in 139 vertebrae were reviewed for medial or caudal perforations on coronal projection. For the evaluation of the methodological accuracy, virtual and intraoperative images were compared, and the angulation of the pedicle screw to the midsagittal line was measured. RESULTS Pedicle perforations were recorded in 3.2% of pedicle screws. None of the perforated pedicle screws damaged a nerve root. The difference in angulation between the actual and virtual pedicle screws was 2.8° ± 1.9°. CONCLUSIONS The use of the StealthStation TREON plus navigation system in combination with the O-arm system showed the highest accuracy for spinal navigation compared with other studies that used traditional image acquisition and registration for navigation.

S-100B and NSE: markers of initial impact of subarachnoid haemorrhage and their relation to vasospasm and outcome

S100-B and neuron specific enolase (NSE) are known predictors of outcome in head injured and stroke patients. This study was conducted to test the hypothesis that S-100B and NSE can predict the development of vasospasm and outcome within the first 3 days after subarachnoid haemorrhage (SAH). Fifty-one SAH patients (mean age 51+/-11 years, male : female ratio 1.0 : 1.6, mean World Federation of Neurological Surgeons [WFNS] Grade 3+/-1.5) were included in the study. S100-B and NSE were recorded in venous blood across the first 3 days post-SAH. Vasospasm was diagnosed if mean blood flow velocity of the middle cerebral artery was greater than 120 cm/s and Lindegaard ratio >3. Glasgow Outcome Score (GOS) and cranial CT scans were recorded at 6 months. Normal, intermediate and high S-100B values were seen in 24%, 51% and 25% of patients, respectively. In patients with S-100B>1 microg/L, Fisher Grade 4 and WFNS 4-5 were both seen in 77% of cases. S-100B was significantly higher in those patients who did not develop vasospasm. In addition, S-100B values were significantly higher in those patients who died than in those with unfavourable or favourable outcome. NSE was normal, intermediate and high in 82%, 8% and 10% of patients, respectively. Patients with WFNS 4-5 and/or Fisher Grade 4 had significantly higher NSE values than all others. Across the first 3 days after SAH, measuring S-100B is useful to predict outcome and vasospasm.

The prediction of long-term outcome after subarachnoid hemorrhage as measured by the Short Form-36 Health Survey

The Glasgow Outcome Scale (GOS) score is widely used to assess outcome after a subarachnoid hemorrhage (SAH). Patients who have recovered fully or with a mild disability (GOS scores 4 and 5) frequently complain about difficulties in conducting their daily activities. The Short Form-36 (SF-36) Health Survey is a questionnaire that assesses outcomes in multiple categories. This study was conducted to compare the quality of outcome assessment between the SF-36 Health Survey and GOS scores. A total of 128 patients with SAH (all data expressed as mean+/-standard deviation) aged 53.1+/-12.1 years, and a mean Hunt and Hess grade on admission of 2+/-1, were retrospectively included in the study. Medical charts were reviewed to assess previous medical history, location of the aneurysm and the presence of vasospasm. The SF-36 and GOS scores were collected in structured interviews approximately 5 years (+/-2 years) after the SAH. The SF-36 data were compared to a historical healthy control cohort of 2,474 individuals. The results showed that 52% of patients experienced a favourable outcome after SAH (GOS scores 4 and 5). Vasospasm was recorded in 25% of patients. However, the average SF-36 results were lower in all tested categories for patients after SAH than the healthy normal controls. None of the SF-36 categories except physical function correlated significantly with the GOS score. Aneurysm location did not have an impact on SF-36 data. Patients after a SAH assessed as GOS score 5 are significantly impaired in social functioning and general health. We conclude that patients continue to suffer neuropsychological deficits years after a SAH. The GOS score is a rough outcome measure that primarily focuses on physical functioning. SF-36 is a useful tool to include in the neuropsychological outcome assessment of patients with SAH.

Spontaneous Intracerebral Hemorrhage With Ventricular Extension and the Grading of Obstructive Hydrocephalus: The Prediction of Outcome of a Special Life-Threatening Entity

BACKGROUND:Primary spontaneous intracerebral hemorrhage (SICH) with secondary intraventricular hemorrhage (IVH) accounts for the highest in-hospital mortality after stroke. OBJECTIVE:To analyze predictors and the role of acute hydrocephalus in outcome, especially 30-day mortality or an unfavorable outcome at 6 months. In addition, a new risk stratification tool for SICH- IVH was developed. METHODS:Hospital charts of 104 of 110 SICH-IVH patients were retrospectively analyzed. All patients underwent at least 1 external ventricular drainage. Multivariate logistic regression analysis was used to identify independent prognostic predictors for 30-day mortality and outcome. Outcome was determined by the modified Rankin Scale. On the basis of the independent predictors, we developed an IVH scoring system. The IVH score was tested with prospective data from 51 patients and was compared with established intracerebral hemorrhage scoring systems. RESULTS:An initial SICH volume of 60 cm3 or greater, severe hydrocephalus, Glasgow Coma Scale score of 8 or less, and age 70 years and older were independent outcome predictors. Different cutoff values for the prediction of 30-day mortality and functional outcome were defined. The IVH score was best for the prediction of 30-day mortality. CONCLUSION:Severe hydrocephalus is an independent predictor of 30-day mortality in SICH with ventricular extension. The IVH score is a simple and reliable tool for predicting 30-day mortality.

Cytosolic Ca2+ Oscillations in Human Cerebrovascular Endothelial Cells after Subarachnoid Hemorrhage

Molecular mechanisms of cerebral vasospasm after subarachnoid hemorrhage (SAH) include specific modes of cell signaling like activation of nuclear factor (NF)-kB and vascular cell adhesion molecules (VCAM)-1 expression. The studys hypothesis is that cisternal cerebral spinal fluid (CSF) from patients after SAH may cause Ca2+ oscillations which induce these modes of vascular inflammation in an in vitro model of human cerebral endothelial cells (HCECs). HCECs were incubated with cisternal CSF from 10 SAH patients with confirmed cerebral vasospasm. The CSF was collected on days 5 and 6 after hemorrhage. Cytosolic Ca2+ concentrations and cell contraction as an indicator of endothelial barrier function were examined by fura-2 microflurometry. Activation of NF-κB and VCAM-1 expression were measured by immunocytochemistry. Incubation of HCEC with SAH-CSF provoked cytosolic Ca2+ oscillations (0.31 ± 0.09 per min), cell contraction, NF-κB activation, and VCAM-1 expression, whereas exposure to native CSF had no significant effect. When endoplasmic reticulum (ER) Ca2+-ATPase and ER inositol trisphosphate (IP3)-sensitive Ca2+ channels were blocked by thapsigargin or xestospongin, the frequency of the Ca2+ oscillations was reduced significantly. In analogy to the reduction of Ca2+ oscillation frequency, the blockers impaired HCEC contraction, NF-κB activation, and VCAM-1 expression. Cisternal SAH-CSF induces cytosolic Ca2+ oscillations in HCEC that results in cellular constriction, NF-κB activation, and VCAM-1 expression. The Ca2+ oscillations depend on the function of ER Ca2+-ATPase and IP3-sensitive Ca2+ channels.

2-Octyl-cyanoacrylate for wound closure in cervical and lumbar spinal surgery

It is claimed that wound closure with 2-octyl-cyanoacrylate has the advantages that band-aids are not needed in the postoperative period, that the wound can get in contact with water and that removal of stitches is not required. This would substantially enhance patient comfort, especially in times of reduced in-hospital stays. Postoperative wound infection is a well-known complication in spinal surgery. The reported infection rates range between 0% and 12.7%. The question arises if the advantages of wound closure with 2-octyl-cyanoacrylate in spinal surgery are not surpassed by an increase in infection rate. This study has been conducted to identify the infection rate of spinal surgery if wound closure was done with 2-octyl-cyanoacrylate. A total of 235 patients with one- or two-level surgery at the cervical or lumbar spine were included in this prospective study. Their pre- and postoperative course was evaluated. Analysis included age, sex, body mass index, duration and level of operation, blood examinations, 6-week follow-up and analysis of preoperative risk factors. The data were compared to infection rates of similar surgeries found in a literature research and to a historical group of 503 patients who underwent wound closure with standard skin sutures after spine surgery. With the use of 2-octyl-cyanoacrylate, only one patient suffered from postoperative wound infection which accounts for a total infection rate of 0.43%. In the literature addressing infection rate after spine surgery, an average rate of 3.2% is reported. Infection rate was 2.2% in the historical control group. No risk factor could be identified which limited the usage of 2-octyl-cyanoacrylate. 2-Octyl-cyanoacrylate provides sufficient wound closure in spinal surgery and is associated with a low risk of postoperative wound infection.

Cerebral energy failure after subarachnoid hemorrhage: the role of relative hyperglycolysis.

After subarachnoid hemorrhage (SAH) cerebral metabolism is significantly impaired. Hyperglycolysis describes the reduction of oxidative metabolism followed by a relative increase of anaerobic glycolysis to maintain energy supply. This phenomenon is known in head injury but has not as yet been shown after SAH. This study was conducted to test the hypothesis that hyperglycolysis is present in SAH patients and is associated with vasospasm. A total of 105 measurements were conducted on 21 SAH patients (age 49+/-15 years, median World Federation of Neurosurgical Societies Grade 4) over the first 5 days following admission. Arteriovenous differences were calculated for oxygen (avDO2) and glucose (avDGlc). Relative hyperglycolysis was defined as metabolic ratio (MR=avDO2[mmol/L]/avDGlc[mmol/L])<3.44. Jugular-venous saturation for oxygen (SjvO2), mean arterial blood pressure (MAP), intracranial pressure (ICP), cerebral perfusion pressure (CPP) were monitored. Relative hyperglycolyis was recorded in 34% of studies after SAH. In hyperglycolytic studies both jugular-venous lactate and SjvO2 were significantly elevated (jugular-venous lactate 14.9+/-9.9 vs. 11.8+/-5.5 mg/dL, p=0.04; SjvO2: 70.0+/-18% vs. 81.7+/-9%, p=0.002). Relative hyperglycolysis is associated with outcome after SAH. In patients who died after SAH almost 50% of studies showed hyperglycolysis, whereas patients who survived without neurological deficit had no hyperglycolytic events. Relative hyperglycolysis is a common event after SAH. It may be associated with relative hyperemia but most importantly with outcome.

Mean hemoglobin concentration after acute subarachnoid hemorrhage and the relation to outcome, mortality, vasospasm, and brain infarction.

Lower mean hemoglobin (HGB) levels are associated with unfavorable outcome after spontaneous subarachnoid hemorrhage (SAH). Currently, there is no cutoff level for mean HGB levels associated with unfavorable outcome. This study was conducted to evaluate a threshold for mean HGB concentrations after SAH, and to observe the relation to outcome. The medical records of 702 patients with spontaneous SAH were reviewed. Predictors of outcome were proved by univariate analysis. Predictors with p<0.1 were included in a multivariate binary logistic regression model. Cutoff points for mean HGB levels were calculated by receiver operating characteristic curve analysis. Mean HGB was 11.9 g/dl (±standard deviation [SD] 1.7 g/dl) in patients with favorable outcome compared to 10.8 g/dl (±SD 1.1g/dl) in patients with unfavorable outcome (p<0.001). The highest Youdens index value was found for a HGB cutoff at 11.1 g/dl. In a binary logistic regression model, predictors of unfavorable outcome were identified as an initially high Hunt-Hess grade (odds ratio [OR]: 7.7; 95% confidence interval [CI]: 4.4-13.4; p<0.001), cerebral infarction on a CT scan during hospital stay (OR: 3.8; 95% CI: 2.0-7.3; p<0.001), rebleeding during the hospital stay (OR: 3.5; 95% CI: 1.6-8.0; p=0.002), mean HGB concentration <11.1g/dl (OR: 3.3; 95% CI: 2.0-5.3; p<0.001), and hydrocephalus (OR: 2.3; 95% CI: 1.4-3.7; p=0.001). In conclusion, a mean HGB concentration <11.1 g/dl during the hospital stay was associated with unfavorable outcome after acute SAH.

Parenteral and enteral nutrition in the management of neurosurgical patients in the intensive care unit

The iatrogenic malnutrition of neurosurgical patients in intensive care units (ICU) is an underestimated problem. It may cause a decrease in plasma albumin and oncotic pressure, leading to an increase in the amount of water entering the brain and increased intracranial pressure (ICP). This study was conducted to test the hypothesis that combined high-protein parenteral and enteral nutrition is beneficial for neurosurgical patients in ICU. A total of 202 neurosurgical patients in ICU (mean age+/-standard deviation, 56 years+/-16 years; male:female=1.2:1) were studied. Two consecutive 1-year time periods were compared, during which two different nutritional regimens were followed. In the first time period (Y1) patients were given a low-protein/high-fat formulation parenterally, followed by a standard enteral regimen. In the second time period (Y2) a protein-rich, combined parenteral and enteral diet was prospectively administered. The Glasgow Outcome Score was measured at 3-6 months after discharge. The following clinical parameters were recorded during the first 2 weeks after admission: ICP; albumin; cholinesterase (CHE); daily hours of ICP > 20 mmHg and cerebral perfusion pressure<70 mmHg; and Acute Physiology and Chronic Health Evaluation II (APACHE II) score. It was found that overall albumin (32.4 g/L+/-4.1g/L vs. 27.5 g/L+/-3.6g/L) and CHE was higher during Y2, although the total energy supply, glucose and fat intake was lower. Higher GOS scores were seen when patients had lower APACHE II scores and received the Y2 nutritional regimen. During Y2, the total hours of ICP > 20 mmHg were fewer. With the Y2 nutrition, maintenance of adequate cerebral perfusion required less catecholamine medication and colloidal fluid replacement. Therefore, adequate nutrition is an important parameter in the management of neurosurgical patients in ICU.